Orcein (Orcein, archil, orchil, lacmus, litmus, orcein, orsin, litmus, E182) - kristal gbara ọchịchịrị. Ha na-agbanwe agba na-acha uhie uhie na gburugburu acidic na-acha anụnụ anụnụ na nke alkaline. Usoro kemịkalụ C28H24N2O7.
E wepụrụ ihe mgbakwunye na ndepụta nke "Ihe mgbakwunye nri maka mmepụta nri" na Sanitary na Epidemiological Rule and Regulations (SanPiN 2.3.2.2364-08) na 2008.